if i would place interior objects the "walls down vision " ( how is that called? ) functions as normaly.

Edit: seems it's bound to that sport where the building is located, between trees and tree free mountainside in Vain, reloaded an oldersave and the "look inside the building" works on the otherspots as normal. It works as normal in an other region than Vain aswell with the save where the problem has occoured.
i add a save where my workers ahs builded a smallshack succefully wihtout the problem on ther location in southern direction. maybe it helps. if not already aware of it.
https://www.dropbox.com/s/soczj5y0w8yt6 ... t.rar?dl=0